Visual Basic

10-Oct-06 5:23

ByVal passes an argument to a method, well, by Value. It passes the actual value of the argument to the method you're calling by pushing that value on the call stack. When the method gets control, it pops the values off the stack and uses them.

ByRef passes an argument by pointer. Instead of passing the value, it passes an address to the value stored in memory somewhere. The addess is pushed onto the stack and passed to the method, which pops that address off the call stack, and now knows where in memory to find the value.

You can find out more here[^].

Dave Kreskowiak
Microsoft MVP - Visual Basic

IE popup menu

m_mor10-Oct-06 0:05

m_mor

10-Oct-06 0:05

I have a question about right mouse click popup menu in IE.
I try write a program that add a new item into popup menu's items(I want program popup menu).but i don't know any thing about this .
please help me .

computer

Re: IE popup menu

UltraCoder10-Oct-06 8:42

UltraCoder

10-Oct-06 8:42

That's called a "Context Menu" or "Context Menu Strip".

Comm B/W Layers

ravimorampudi10-Oct-06 0:02

10-Oct-06 0:02

Hi i am a beginer plz give me a answer

How d comm take place b/w Business layer,Presentation Layer in 3.Tier implementation

Thanks...

Re: Comm B/W Layers

Dave Kreskowiak10-Oct-06 5:20

10-Oct-06 5:20

Simple class instantiation and method calls. There's no magic going on between layers.

Dim myBusObj As New BusinessObject
myBusObj.ValidateSomeData(data)

Dave Kreskowiak
Microsoft MVP - Visual Basic

Stored Procedure

ravimorampudi9-Oct-06 23:58

9-Oct-06 23:58

Hi,

I have a stored procedure and it is returning a table as a result.
How can i call d proc & Capture table from Vb.Net using Connected arch

Thanks...

hrodberaht10-Oct-06 0:23

10-Oct-06 0:23

Hi
You can retieve data using a stored procedure in the same way as any other query. There is other (more optimal) ways to retrieve data using a SP, but this is the simplest.

Example:

'---Create Connection
Dim ConnectionString As New SqlClient.SqlConnectionStringBuilder
ConnectionString.DataSource = "localhost" 'ServerName
ConnectionString.InitialCatalog = "MyDataBase" 'DatabaseName
ConnectionString.IntegratedSecurity = True

'Open Connction
Dim Connection As New SqlClient.SqlConnection(ConnectionString.ConnectionString)
Connection.Open()

'---Create/Open Reader
Dim Reader As SqlClient.SqlDataReader
Dim Command As System.Data.SqlClient.SqlCommand = New System.Data.SqlClient.SqlCommand("MyStoredProcedureName", Connection)
Command.CommandType = CommandType.StoredProcedure 'Optional
Reader = Command.ExecuteReader

While Reader.Read
MsgBox("Field 0 :" & Reader.Item(0).ToString)
MsgBox("Field 1 :" & Reader.Item(1).ToString)
End While

'Close Reader
Reader.Close()
'Close Connection
Connection.Close()

ravimorampudi10-Oct-06 0:28

10-Oct-06 0:28

Thanks
but genarally we r use Exectenonquery() for stred proc
is tere any othre way by using nonquery

Thanks

hrodberaht10-Oct-06 0:40

10-Oct-06 0:40

ExecuteNonQuery only returns Rows Affected, and populates any Output paramters that was mapped. So this would not work well if you need a resultset.

You could use ExecuteReader/Command, or Use a DataAdapter to retrieve the data.

ravimorampudi10-Oct-06 0:24

10-Oct-06 0:24

better

Determining Object Types

hrodberaht9-Oct-06 23:52

9-Oct-06 23:52

I need to determine an objects datatype. Using TypeOf works fine when the object has been instantiated (declared as New), but otherwise (when the object is still "nothing"), it does not detect the type.

Any idea how I can detect datatypes of un-instantiated objects?.

Dave Kreskowiak10-Oct-06 5:18

10-Oct-06 5:18

Perhaps you're looking for

var.GetType()

Dave Kreskowiak
Microsoft MVP - Visual Basic

hrodberaht10-Oct-06 5:39

10-Oct-06 5:39

Hi, I've already tried that, but it seems that the object must be instantiated before you can use the GetType property.

I need to check for a limited amount of types, so I'm thinking of writing a function and use overloading with the object as parameter, which returns a text/enumrated value, indicating what type it is. Would like to figure out how VB does it behind the scenes though.

Dave Kreskowiak10-Oct-06 8:00

10-Oct-06 8:00

My bad. I was trying it on something that WAS instantiated. I just didn't know it at the time. It looks like you can't, unless you actually have an instance of the object. I've never come acrossed a case where I needed to do anything like this.

Why would you want to do this anyway?

Dave Kreskowiak
Microsoft MVP - Visual Basic

hrodberaht10-Oct-06 21:27

10-Oct-06 21:27

I have a centralized function which populates data/executes commands from SQLServer and does some exception handling etc. A parameter which will populated with information such as RowsAffected or DataReaders, is of type "Object".

When calling the function, and a SQLDataReader is used as parameter, is when I have a prob. SQLDataReaders don't have any constructors, so when the function tries to detect what type the object is (Using TypeOF()), it can't (Because its "Nothing").

In the end, I think you're right. I should problably take a different approach.

Thanks for your help in any case.

Dave Kreskowiak11-Oct-06 1:54

11-Oct-06 1:54

Oh man, this gets ugly! A much better approach is to "un-generalize" it. Overloaded functions would work much better. You can still combine the common stuff between different versions of this, like a method to just call a stored proc and return the result set, though.

Dave Kreskowiak
Microsoft MVP - Visual Basic

hrodberaht11-Oct-06 2:09